This invention relates to reinforced hose, couplings and assemblies, more particularly to improvements that increase the performance and durability of the hose and coupling assembly.
In the design of coupling assemblies for fairly heavy duty hose, for example rotary drill, choke and kill and motion compensator hose, two important criteria are reduction in length and weight of the coupling without compromising working and burst pressure capability, and end seal reliability. One approach that has been taken, as disclosed in U.S. Pat. No. 4,143,892 to Murphy et al, is to taper the coupling sleeve into a frustro-conical shape with an enlarged end adjacent the nipple of the coupling. At the base of this frustrum, the pitch of certain of the wire reinforcements has been increased in stepped fashion with the individual wires of increased pitch being longitudinally and/or radially nonuniformly spaced apart, and then embedded in an anchoring matrix of polymeric resin. However, certain gases, particularly H.sub.2 S, can permeate the seal and tube material and destroy the reinforcement anchoring matrix in the coupling, so that the wires can move as the hose is pressurized. The tube material also prevents H.sub.2 S permeation into the hose body. If the wires deform at high pressure, the burst resistance is lowered and the hose does not perform optimally. By using a fluoroelastomeric material for the seal and tube liner of the coupling, H.sub.2 S in up to 20% concentrations is not able to permeate into the body of the hose and the wire will remain firmly anchored.
Another objective is to improve the overall sealing and strength of this hose coupling. As service requirements become more demanding, the need for higher pressure hoses has developed. Working pressure of up to 15,000 p.s.i. are now necessary. Also, tests such as the Lloyds of London Fire Test (700.degree. C. [1294.degree. F.] at a working pressure of either 10,000 or 15,000 p.s.i. for 30 minutes) have been established for hoses to be used on oil rigs in the North Sea. A new seal is needed that will meet these more demanding operating conditions. Also in conjunction with these tests and overall more demanding operating conditions, heat resistant ceramic fibers have heretofore been placed beneath the cover of the hose to protect the inner hose from exposure to high temperatures.
Couplings, such as the one disclosed in U.S. Pat. No. 4,143,892 to Murphy et al, may have a tendency to fail at sufficiently high pressure. The primary site of failure in couplings such as these has been found to be where the seal and coupling seal ring seat against the fitting. Therefore, an object of this invention is to provide a modified seal and coupling seal ring to increase the reliability of couplings of this design in high pressure service. Additional references that are relevant to this disclosure include U.S. Pat. Nos. 2,473,441 (Muller), 2,506,494 (Feler et al), 2,940,778 (Kaiser) and 3,217,282 (Chevalier et al).